Protecting Privacy of Pregnant and LGBTQ+ Research Participants

This Viewpoint summarizes existing federal regulations aimed at protecting research data, describes the challenges of enforcing these regulations, and discusses how evolving privacy technologies could be used to reduce health disparities and advance health equity among pregnant and LGBTQ+ research participants.

Incidence of Adolescent Syncope and Related Injuries Following Vaccination and Routine Venipuncture

PURPOSE

Vaccination is associated with syncope in adolescents. However, incidence of vaccine-associated syncope and resulting injury, and how it compares to syncope incidence following other medical procedures, is not known. Here, we describe the incidence of syncope and syncope-related injury in adolescents following vaccination and routine venipuncture.

METHODS

We identified all Kaiser Permanente Northwest members ages 9-18 years with a vaccination or routine venipuncture and a same-day International Classification of Diseases diagnosis of syncope from 2013 through 2019. All cases were chart reviewed to establish chronology of events (vaccination, venipuncture, syncope, and injury, as applicable) and to attribute cause to vaccination or venipuncture. Incidence rates for vaccine-associated and venipuncture-associated syncope were calculated overall, by sex and age group. Syncope events resulting in injury were assessed for each event type.

RESULTS

Of 197,642 vaccination and 12,246 venipuncture events identified, 549 vaccination and 67 venipuncture events had same-day syncope codes. Chart validation confirmed 59/549 (10.7%) events as vaccine-associated syncope, for a rate of 2.99 per 10,000 vaccination events (95% confidence interval (CI): 2.27-3.85) and 20/67 (29.9%) events as venipuncture-associated syncope, for a rate of 16.33 per 10,000 venipuncture events (95% CI: 9.98-25.21). The incidence rate ratio of vaccine-associated to venipuncture-associated syncope events was 0.18 (95% CI: 0.11-0.31). The incidence of vaccine-associated syncope increased with each additional simultaneously administered vaccine, from 1.51 per 10,000 vaccination events (95% CI: 0.93-2.30) following a single vaccine to 9.94 per 10,000 vaccination events (95% CI: 6.43-14.67) following three or more vaccines. Syncope resulted in injury in about 15% of both vaccine and venipuncture events.

DISCUSSION

Syncope occurs more commonly following venipuncture than vaccination. The number of simultaneously administered vaccines is a risk factor for postvaccination syncope in adolescents.

Prediction of Effectiveness and Toxicities of Immune Checkpoint Inhibitors Using Real-World Patient Data

PURPOSE

Although immune checkpoint inhibitors (ICIs) have improved outcomes in certain patients with cancer, they can also cause life-threatening immunotoxicities. Predicting immunotoxicity risks alongside response could provide a personalized risk-benefit profile, inform therapeutic decision making, and improve clinical trial cohort selection. We aimed to build a machine learning (ML) framework using routine electronic health record (EHR) data to predict hepatitis, colitis, pneumonitis, and 1-year overall survival.

METHODS

Real-world EHR data of more than 2,200 patients treated with ICI through December 31, 2018, were used to develop predictive models. Using a prediction time point of ICI initiation, a 1-year prediction time window was applied to create binary labels for the four outcomes for each patient. Feature engineering involved aggregating laboratory measurements over appropriate time windows (60-365 days). Patients were randomly partitioned into training (80%) and test (20%) sets. Random forest classifiers were developed using a rigorous model development framework.

RESULTS

The patient cohort had a median age of 63 years and was 61.8% male. Patients predominantly had melanoma (37.8%), lung cancer (27.3%), or genitourinary cancer (16.4%). They were treated with PD-1 (60.4%), PD-L1 (9.0%), and CTLA-4 (19.7%) ICIs. Our models demonstrate reasonably strong performance, with AUCs of 0.739, 0.729, 0.755, and 0.752 for the pneumonitis, hepatitis, colitis, and 1-year overall survival models, respectively. Each model relies on an outcome-specific feature set, though some features are shared among models.

CONCLUSION

To our knowledge, this is the first ML solution that assesses individual ICI risk-benefit profiles based predominantly on routine structured EHR data. As such, use of our ML solution will not require additional data collection or documentation in the clinic.

Participant-guided development of bilingual genomic educational infographics for Electronic Medical Records and Genomics Phase IV study

OBJECTIVE

Developing targeted, culturally competent educational materials is critical for participant understanding of engagement in a large genomic study that uses computational pipelines to produce genome-informed risk assessments.

MATERIALS AND METHODS

Guided by the Smerecnik framework that theorizes understanding of multifactorial genetic disease through 3 knowledge types, we developed English and Spanish infographics for individuals enrolled in the Electronic Medical Records and Genomics Network. Infographics were developed to explain concepts in lay language and visualizations. We conducted iterative sessions using a modified "think-aloud" process with 10 participants (6 English, 4 Spanish-speaking) to explore comprehension of and attitudes towards the infographics.

RESULTS

We found that all but one participant had "awareness knowledge" of genetic disease risk factors upon viewing the infographics. Many participants had difficulty with "how-to" knowledge of applying genetic risk factors to specific monogenic and polygenic risks. Participant attitudes towards the iteratively-refined infographics indicated that design saturation was reached.

DISCUSSION

There were several elements that contributed to the participants' comprehension (or misunderstanding) of the infographics. Visualization and iconography techniques best resonated with those who could draw on prior experiences or knowledge and were absent in those without. Limited graphicacy interfered with the understanding of absolute and relative risks when presented in graph format. Notably, narrative and storytelling theory that informed the creation of a vignette infographic was most accessible to all participants.

CONCLUSION

Engagement with the intended audience who can identify strengths and points for improvement of the intervention is necessary to the development of effective infographics.

Longitudinal adherence to breast cancer surveillance following cancer genetic testing in an integrated health care system

PURPOSE

Screening with mammography and breast magnetic resonance imaging (MRI) is an important risk management strategy for individuals with inherited pathogenic variants (PVs) in genes associated with increased breast cancer risk. We describe longitudinal screening adherence in individuals who underwent cancer genetic testing as part of usual care in a vertically integrated health system.

METHODS

We determined the proportion time covered (PTC) by annual mammography and breast MRI for individuals with PVs in TP53, BRCA1, BRCA2, PALB2, NF1, CHEK2, and ATM. We determined time covered by biennial mammography beginning at age 50 years for individuals who received negative results, uncertain results, or with PVs in genes without specific breast cancer screening recommendations.

RESULTS

One hundred and forty individuals had PVs in TP53, BRCA1, BRCA2, PALB2, NF1, CHEK2, or ATM. Among these individuals, average PTC was 48% (range 0-99%) for annual screening mammography and 34% (range 0-100%) for annual breast MRI. Average PTC was highest for individuals with PVs in CHEK2 (N = 14) and lowest for individuals with PVs in TP53 (N = 3). Average PTC for biennial mammography (N = 1,027) was 49% (0-100%).

CONCLUSION

Longitudinal screening adherence in individuals with PVs in breast cancer associated genes, as measured by the proportion of time covered, is low; adherence to annual breast MRI falls below that of annual mammography. Additional research should examine screening behavior in individuals with PVs in breast cancer associated genes with a goal of developing interventions to improve adherence to recommended risk management.

Conducting inclusive research in genetics for transgender, gender-diverse, and sex-diverse individuals: Case analyses and recommendations from a clinical genomics study

A person's phenotypic sex (i.e., endogenous expression of primary, secondary, and endocrinological sex characteristics) can impact crucial aspects of genetic assessment and resulting clinical care recommendations. In studies with genetics components, it is critical to collect phenotypic sex, information about current organ/tissue inventory and hormonal milieu, and gender identity. If researchers do not carefully construct data models, transgender, gender diverse, and sex diverse (TGSD) individuals may be given inappropriate care recommendations and/or be subjected to misgendering, inflicting medical and psychosocial harms. The recognized need for an inclusive care experience should not be limited to clinical practice but should extend to the research setting, where researchers must build an inclusive experience for TGSD participants. Here, we review three TGSD participants in the Family History and Cancer Risk Study (FOREST) to critically evaluate sex- and gender-related survey measures and associated data models in a study seeking to identify patients at risk for hereditary cancer syndromes. Furthermore, we leverage these participants' responses to sex- and gender identity-related questions in FOREST to inform needed changes to the FOREST data model and to make recommendations for TGSD-inclusive genetics research design, data models, and processes.

Risk management actions following genetic testing in the Cancer Health Assessments Reaching Many (CHARM) Study: A prospective cohort study

BACKGROUND

Genetic testing can identify cancer risk early, enabling prevention and early detection. We describe use of risk management interventions following genetic testing in the Cancer Health Assessment Reaching Many (CHARM) study. CHARM assessed risk and provided genetic testing to low income, low literacy, and other underserved populations that historically face barriers to accessing cancer genetic services.

METHODS

CHARM was implemented in Kaiser Permanente Northwest (KPNW) and Denver Health (DH) between 2018 and 2020. We identified post-testing screening (mammography, breast MRI, colonoscopy) and surgical (mastectomy, oophorectomy) procedures using electronic health records. We examined utilization in participants who did and did not receive actionable risk management recommendations from study genetic counselors following national guidelines.

RESULTS

CHARM participants were followed for an average of 15.4 months (range: 0.4-27.8 months) after results disclosure. Less than 2% (11/680) received actionable risk management recommendations (i.e., could be completed in the initial years following testing) based on their test result. Among those who received actionable recommendations, risk management utilization was moderate (54.5%, 6/11 completed any procedure) and varied by procedure (mammogram: 0/3; MRI: 2/4; colonoscopy: 4/5; mastectomy: 1/5; oophorectomy: 0/3). Cancer screening and surgery procedures were rare in participants without actionable recommendations.

CONCLUSION

Though the number of participants who received actionable risk management recommendations was small, our results suggest that implementing CHARM's risk assessment and testing model increased access to evidence-based genetic services and provided opportunities for patients to engage in recommended preventive care, without encouraging risk management overuse.

Epidemiology of Upper Limb Complex Regional Pain Syndrome in a Retrospective Cohort of Persons Aged 9-30 Years, 2002-2017

Introduction This paper describes the epidemiology and clinical presentation of complex regional pain syndrome (CRPS) in a large, integrated health care delivery system; and CRPS incidence rates (IRs) over a time period spanning human papillomavirus (HPV) vaccine licensure and published case reports of CRPS following HPV vaccination. Methods The authors examined CRPS diagnoses in patients aged 9-30 years between January 2002 and December 2017 using electronic medical records, excluding patients with lower limb diagnoses only. Medical record abstraction and adjudication were conducted to verify diagnoses and describe clinical characteristics. CRPS IRs were calculated for 3 periods: Period 1 (2002-2006: before HPV vaccine licensure), Period 2 (2007-2012: after licensure but before published case reports), and Period 3 (2013-2017: after published case reports). Results A total of 231 individuals received an upper limb or unspecified CRPS diagnosis code during the study period; 113 cases were verified through abstraction and adjudication. Most verified cases (73%) were associated with a clear precipitating event (eg, non-vaccine-related injury, surgical procedure). The authors identified only 1 case in which a practitioner attributed CRPS onset to HPV vaccination. Twenty-five incident cases occurred in Period 1 (IR = 4.35/100,000 person-years (PY), 95% confidence interval (CI) = 2.94-6.44), 42 in Period 2 (IR = 5.94/100,000 PY, 95% CI = 4.39-8.04), and 29 in Period 3 (IR = 4.53/100,000 PY, 95% CI = 3.15-6.52); differences between periods were not statistically significant. Conclusion These data provide a comprehensive assessment of the epidemiology and characteristics of CRPS in children and young adults and provide further reassurance about the safety of HPV vaccination.

Evaluating cancer genetic services in a safety net system: overcoming barriers for a lasting impact beyond the CHARM research project

Underserved patients face substantial barriers to receiving cancer genetic services. The Cancer Health Assessments Reaching Many (CHARM) study evaluated ways to increase access to genetic testing for individuals in underserved populations at risk for hereditary cancer syndromes (HCS). Here, we report the successful implementation of CHARM in a low-resource environment and the development of sustainable processes to continue genetic risk assessment in this setting. The research team involved key clinical personnel and patient advisors at Denver Health to provide input on study methods and materials. Through iterative and collaborative stakeholder engagement, the team identified barriers and developed solutions that would both facilitate participation in CHARM and be feasible to implement and sustain long term in clinical care. With a focus on infrastructure building, educational modules were developed to increase awareness among referring providers, and standard methods of identifying and managing HCS patients were implemented in the electronic medical record. Three hundred sixty-four DH patients successfully completed the risk assessment tool within the study, and we observed a sustained increase in referrals to genetics for HCS (from 179 in 2017 to 427 in 2021 post-intervention). Implementation of the CHARM study at a low-resourced safety net health system resulted in sustainable improvements in access to cancer genetic risk assessment and services that continue even after the study ended.Trial registration NCT03426878.

Returning integrated genomic risk and clinical recommendations: The eMERGE study

PURPOSE

Assessing the risk of common, complex diseases requires consideration of clinical risk factors as well as monogenic and polygenic risks, which in turn may be reflected in family history. Returning risks to individuals and providers may influence preventive care or use of prophylactic therapies for those individuals at high genetic risk.

METHODS

To enable integrated genetic risk assessment, the eMERGE (electronic MEdical Records and GEnomics) network is enrolling 25,000 diverse individuals in a prospective cohort study across 10 sites. The network developed methods to return cross-ancestry polygenic risk scores, monogenic risks, family history, and clinical risk assessments via a genome-informed risk assessment (GIRA) report and will assess uptake of care recommendations after return of results.

RESULTS

GIRAs include summary care recommendations for 11 conditions, education pages, and clinical laboratory reports. The return of high-risk GIRA to individuals and providers includes guidelines for care and lifestyle recommendations. Assembling the GIRA required infrastructure and workflows for ingesting and presenting content from multiple sources. Recruitment began in February 2022.

CONCLUSION

Return of a novel report for communicating monogenic, polygenic, and family history-based risk factors will inform the benefits of integrated genetic risk assessment for routine health care.

Accelerated curation of checkpoint inhibitor-induced colitis cases from electronic health records

Objective

Automatically identifying patients at risk of immune checkpoint inhibitor (ICI)-induced colitis allows physicians to improve patientcare. However, predictive models require training data curated from electronic health records (EHR). Our objective is to automatically identify notes documenting ICI-colitis cases to accelerate data curation.

Materials and Methods

We present a data pipeline to automatically identify ICI-colitis from EHR notes, accelerating chart review. The pipeline relies on BERT, a state-of-the-art natural language processing (NLP) model. The first stage of the pipeline segments long notes using keywords identified through a logistic classifier and applies BERT to identify ICI-colitis notes. The next stage uses a second BERT model tuned to identify false positive notes and remove notes that were likely positive for mentioning colitis as a side-effect. The final stage further accelerates curation by highlighting the colitis-relevant portions of notes. Specifically, we use BERT’s attention scores to find high-density regions describing colitis.

Results

The overall pipeline identified colitis notes with 84% precision and reduced the curator note review load by 75%. The segment BERT classifier had a high recall of 0.98, which is crucial to identify the low incidence (<10%) of colitis.

Discussion

Curation from EHR notes is a burdensome task, especially when the curation topic is complicated. Methods described in this work are not only useful for ICI colitis but can also be adapted for other domains.

Conclusion

Our extraction pipeline reduces manual note review load and makes EHR data more accessible for research.

Cost-effectiveness frameworks for comparing genome and exome sequencing versus conventional diagnostic pathways: A scoping review and recommended methods

PURPOSE

Methodological challenges have limited economic evaluations of genome sequencing (GS) and exome sequencing (ES). Our objective was to develop conceptual frameworks for model-based cost-effectiveness analyses (CEAs) of diagnostic GS/ES.

METHODS

We conducted a scoping review of economic analyses to develop and iterate with experts a set of conceptual CEA frameworks for GS/ES for prenatal testing, early diagnosis in pediatrics, diagnosis of delayed-onset disorders in pediatrics, genetic testing in cancer, screening of newborns, and general population screening.

RESULTS

Reflecting on 57 studies meeting inclusion criteria, we recommend the following considerations for each clinical scenario. For prenatal testing, performing comparative analyses of costs of ES strategies and postpartum care, as well as genetic diagnoses and pregnancy outcomes. For early diagnosis in pediatrics, modeling quality-adjusted life years (QALYs) and costs over ≥20 years for rapid turnaround GS/ES. For hereditary cancer syndrome testing, modeling cumulative costs and QALYs for the individual tested and first/second/third-degree relatives. For tumor profiling, not restricting to treatment uptake or response and including QALYs and costs of downstream outcomes. For screening, modeling lifetime costs and QALYs and considering consequences of low penetrance and GS/ES reanalysis.

CONCLUSION

Our frameworks can guide the design of model-based CEAs and ultimately foster robust evidence for the economic value of GS/ES.

Risk-reducing surgery in unaffected individuals receiving cancer genetic testing in an integrated health care system

BACKGROUND

Germline genetic testing enables primary cancer prevention, including through prophylactic surgery. We examined risk-reducing surgeries in unaffected individuals tested for hereditary cancer susceptibly between 2010 and 2018 in the Kaiser Permanente Northwest health system.

METHODS

We used an internal genetic testing database to create a cohort of individuals who received tests including one or more high-penetrance hereditary cancer susceptibility gene. We then identified, after testing, bilateral mastectomy, bilateral salpingo-oophorectomy (BSO), and total hysterectomy procedures in electronic health record and claims data through 2019. We describe surgery utilization by genetic test results and National Comprehensive Cancer Network (NCCN) guidelines.

RESULTS

The cohort included 1020 individuals, 16% with pathogenic/likely pathogenic (P/LP) variants in one or more of the following genes: BRCA1, BRCA2, CHEK2, APC, MUTYH, ATM, MSH2, PALB2, BRIP1, MLH1, MSH6, EPCAM, FLCN, RAD51C, RAD51D, or TP53. Among individuals with P/LP variants making them candidates for mastectomy, BSO, or hysterectomy per NCCN guidelines, 34% (33/97), 24% (23/94), and 8% (1/12), respectively, underwent surgery during follow-up. Fifty-three percent (18/37) of hysterectomies were among APC, BRCA1, and BRCA2 P/LP variant heterozygotes, typically concurrent with BSO. Three individuals with variants of uncertain significance (only) and 22 with negative results had prophylactic surgery after genetic testing.

CONCLUSIONS

Uptake of risk-reducing surgery following usual care genetic testing appears to be lower than in studies that actively recruit high-risk patients and provide testing and follow-up care in specialized settings. Factors in addition to genetic test results and NCCN guidelines motivate prophylactic surgery use and deserve further study.

Literacy-adapted, electronic family history assessment for genetics referral in primary care: patient user insights from qualitative interviews

BACKGROUND

Risk assessment for hereditary cancer syndromes is recommended in primary care, but family history is rarely collected in enough detail to facilitate risk assessment and referral - a roadblock that disproportionately impacts individuals with healthcare access barriers. We sought to qualitatively assess a literacy-adapted, electronic patient-facing family history tool developed for use in diverse, underserved patient populations recruited in the Cancer Health Assessments Reaching Many (CHARM) Study.

METHODS

Interview participants were recruited from a subpopulation of CHARM participants who experienced barriers to tool use in terms of spending a longer time to complete the tool, having incomplete attempts, and/or providing inaccurate family history in comparison to a genetic counselor-collected standard. We conducted semi-structured interviews with participants about barriers and facilitators to tool use and overall tool acceptability; interviews were recorded and professionally transcribed. Transcripts were coded based on a codebook developed using inductive techniques, and coded excerpts were reviewed to identify overarching themes related to barriers and facilitators to family history self-assessment and acceptability of the study tool.

RESULTS

Interviewees endorsed the tool as easy to navigate and understand. However, they described barriers related to family history information, literacy and language, and certain tool functions. Participants offered concrete, easy-to-implement solutions to each barrier. Despite experience barriers to use of the tool, most participants indicated that electronic family history self-assessment was acceptable or preferable in comparison to clinician-collected family history.

CONCLUSIONS

Even for participants who experienced barriers to tool use, family history self-assessment was considered an acceptable alternative to clinician-collected family history. Barriers experienced could be overcome with minor adaptations to the current family history tool.

TRIAL REGISTRATION

This study is a sub-study of the Cancer Health Assessments Reaching Many (CHARM) trial, ClinicalTrials.gov, NCT03426878. Registered 8 February 2018.

Laboratory-related outcomes from integrating an accessible delivery model for hereditary cancer risk assessment and genetic testing in populations with barriers to access

PURPOSE

This study aimed to evaluate the laboratory-related outcomes of participants who were offered genomic testing based on cancer family history risk assessment tools.

METHODS

Patients from clinics that serve populations with access barriers, who are screened at risk for a hereditary cancer syndrome based on adapted family history collection tools (the Breast Cancer Genetics Referral Screening Tool and PREMM₅), were offered exome-based panel testing for cancer risk and medically actionable secondary findings. We used descriptive statistics, electronic health record review, and inferential statistics to explore participant characteristics and results, consultations and actions related to pathogenic/likely pathogenic variants identified, and variables predicting category of findings, respectively.

RESULTS

Of all the participants, 87% successfully returned a saliva kit. Overall, 5% had a pathogenic/likely pathogenic cancer risk variant and 1% had a secondary finding. Almost all (14/15, 93%) participants completed recommended consultations with nongenetics providers after an average of 17 months. The recommended actions (eg, breast magnetic resonance imaging) were completed by 17 of 25 participants. Participant personal history of cancer and PREMM₅ score were each associated with the category of findings (history and colon cancer finding, Fisher's exact P = .02; history and breast cancer finding, Fisher's exact P = .01; PREMM₅^TM score; and colon cancer finding, Fisher's exact P < .001).

CONCLUSION

This accessible model of hereditary cancer risk assessment and genetic testing yielded results that were often acted upon by patients and physicians.

Overcoming barriers in academic-industry partnerships to improve predictive modeling in immuno-oncology

e13581

Background: In the past decade, immunotherapies have revolutionized oncology practice by prolonging patient survival in previously rapidly fatal cancers. However, severe immune toxicities present a challenge, affecting ̃20% and up to 50% of patients on immune monotherapies and combination immunotherapies, respectively. Oncologists must balance toxicity risk with potential efficacy, and pharmaceutical companies have a vested interest in selecting patients with the highest benefit–risk ratio during trial enrollment. Predictive toxicity–efficacy modeling has the potential to guide trial subject selection and clinical care, yet there remains a need for predictive models that can be practically implemented in these settings. Methods: A common academic–industry contract data–transfer framework—wherein academic medical institutions and industry counterparts act in isolation—creates barriers to development of high-quality algorithms with practical applications. In this framework, 1) academic medical institutions provide patient data as a “data dump;” these data are static and cannot be refined—reducing opportunities for quality control; 2) predictive model outcomes may include artifacts that are not identified; 3) manual curation of patient data is required to accurately replicate the model in real-world settings; and 4) lack of clinician participation reduces the potential clinical applications of models and reciprocal benefit to the academic institution. We outline a more contemporary, engaged approach to unite strengths of both partners to achieve a common goal. Results: In 2019, Vanderbilt University Medical Center and GE Healthcare partnered with the goal of enabling safer and more precise immunotherapy use. As part of this work, we formulated a recipe for academic–industry partnerships that offers unique advantages over a static contract framework. In our iterative, interactive approach, 1) clinical and curation experts meet with industry modelers to dynamically refine deidentified data sets by resolving discrepancies in data from different sources (e.g., manually curated vs. structured data); 2) clinical experts iteratively review outputs of predictive models to identify potential artifacts and refine final models; 3) expert curators iterate with in-house machine-learning experts to create algorithms to automate curation of natural language elements from the identified EHR data; and 4) clinical and industry stakeholders participate in regular meetings with modelers to ensure clinical and trial utility of the modeling approach. Conclusions: Compared to data transfer-only relationships, this partnership framework offers an opportunity to develop more informed, higher quality immunotherapy models with clinical and industry applications.

Lessons learned and recommendations for data coordination in collaborative research: The CSER consortium experience

Integrating data across heterogeneous research environments is a key challenge in multi-site, collaborative research projects. While it is important to allow for natural variation in data collection protocols across research sites, it is also important to achieve interoperability between datasets in order to reap the full benefits of collaborative work. However, there are few standards to guide the data coordination process from project conception to completion. In this paper, we describe the experiences of the Clinical Sequence Evidence-Generating Research (CSER) consortium Data Coordinating Center (DCC), which coordinated harmonized survey and genomic sequencing data from seven clinical research sites from 2020 to 2022. Using input from multiple consortium working groups and from CSER leadership, we first identify 14 lessons learned from CSER in the categories of communication, harmonization, informatics, compliance, and analytics. We then distill these lessons learned into 11 recommendations for future research consortia in the areas of planning, communication, informatics, and analytics. We recommend that planning and budgeting for data coordination activities occur as early as possible during consortium conceptualization and development to minimize downstream complications. We also find that clear, reciprocal, and continuous communication between consortium stakeholders and the DCC is equally important to maintaining a secure and centralized informatics ecosystem for pooling data. Finally, we discuss the importance of actively interrogating current approaches to data governance, particularly for research studies that straddle the research-clinical divide.

Integration of stakeholder engagement from development to dissemination in genomic medicine research: Approaches and outcomes from the CSER Consortium

PURPOSE

There is a critical need for genomic medicine research that reflects and benefits socioeconomically and ancestrally diverse populations. However, disparities in research populations persist, highlighting that traditional study designs and materials may be insufficient or inaccessible to all groups. New approaches can be gained through collaborations with patient/community stakeholders. Although some benefits of stakeholder engagement are recognized, routine incorporation into the design and implementation of genomics research has yet to be realized.

METHODS

The National Institutes of Health-funded Clinical Sequencing Evidence-Generating Research (CSER) consortium required stakeholder engagement as a dedicated project component. Each CSER project planned and carried out stakeholder engagement activities with differing goals and expected outcomes. Examples were curated from each project to highlight engagement strategies and outcomes throughout the research lifecycle from development through dissemination.

RESULTS

Projects tailored strategies to individual study needs, logistical constraints, and other challenges. Lessons learned include starting early with engagement efforts across project stakeholder groups and planned flexibility to enable adaptations throughout the project lifecycle.

CONCLUSION

Each CSER project used more than 1 approach to engage with relevant stakeholders, resulting in numerous adaptations and tremendous value added throughout the full research lifecycle. Incorporation of community stakeholder insight improves the outcomes and relevance of genomic medicine research.

Barriers to family history knowledge and family communication among LGBTQ+ individuals in the context of hereditary cancer risk assessment

Openness about identity as lesbian, gay, bisexual, transgender, queer, and other sexual orientations and gender identities (LGBTQ+) may cause strain on relationships between family members, which could lead to limited knowledge of cancer family history and reduced communication with family members. As a result, members of the LGBTQ+ community may have more difficulty accessing genetic counseling services for inherited cancer risk. We applied a mixed-methods approach to explore potential barriers to knowledge of cancer family history and family communication among participants of the Cancer Health Assessments Reaching Many (CHARM) study who self-identified as LGBTQ+. We assessed perceptions of family functioning and communication of genetic test results to family members using survey tools and supplemented these data with 20 in-depth interviews to further assess participant perspectives and experiences. LGBTQ+ participants were more likely to report unhealthy family functioning on the survey tool, and some interviewees endorsed that openness about their LGBTQ+ identity led to strained family relationships and reduced communication about their family history of cancer. Overall, this study identified barriers that may be faced by members of the LGBTQ+ community which could limit their ability to access genetic counseling services for inherited cancer risk.

My Cancer Genome: Coevolution of Precision Oncology and a Molecular Oncology Knowledgebase

PURPOSE

The My Cancer Genome (MCG) knowledgebase and resulting website were launched in 2011 with the purpose of guiding clinicians in the application of genomic testing results for treatment of patients with cancer. Both knowledgebase and website were originally developed using a wiki-style approach that relied on manual evidence curation and synthesis of that evidence into cancer-related biomarker, disease, and pathway pages on the website that summarized the literature for a clinical audience. This approach required significant time investment for each page, which limited website scalability as the field advanced. To address this challenge, we designed and used an assertion-based data model that allows the knowledgebase and website to expand with the field of precision oncology.

METHODS

Assertions, or computationally accessible cause and effect statements, are both manually curated from primary sources and imported from external databases and stored in a knowledge management system. To generate pages for the MCG website, reusable templates transform assertions into reconfigurable text and visualizations that form the building blocks for automatically updating disease, biomarker, drug, and clinical trial pages.

RESULTS

Combining text and graph templates with assertions in our knowledgebase allows generation of web pages that automatically update with our knowledgebase. Automated page generation empowers rapid scaling of the website as assertions with new biomarkers and drugs are added to the knowledgebase. This process has generated more than 9,100 clinical trial pages, 18,100 gene and alteration pages, 900 disease pages, and 2,700 drug pages to date.

CONCLUSION

Leveraging both computational and manual curation processes in combination with reusable templates empowers automation and scalability for both the MCG knowledgebase and MCG website.

Creating accessible Spanish language materials for Clinical Sequencing Evidence-Generating Research consortium genomic projects: challenges and lessons learned

Aim: To increase Spanish speakers' representation in genomics research, accessible study materials on genetic topics must be made available in Spanish. Materials & methods: The Clinical Sequencing Evidence-Generating Research consortium is evaluating genome sequencing for underserved populations. All sites needed Spanish translation of recruitment materials, surveys and return of results. Results: We describe our process for translating site-specific materials, as well as shared measures across sites, to inform future efforts to engage Spanish speakers in research. Conclusion: In translating and adapting study materials for roughly 1000 Spanish speakers across the USA, and harmonizing translated measures across diverse sites, we overcame numerous challenges. Translation should be performed by professionals. Studies must allocate sufficient time, effort and budget to translate and adapt participant materials.

Cancer Health Assessments Reaching Many (CHARM): A clinical trial assessing a multimodal cancer genetics services delivery program and its impact on diverse populations

Advances in the application of genomic technologies in clinical care have the potential to increase existing healthcare disparities. Studies have consistently shown that only a fraction of eligible patients with a family history of cancer receive recommended cancer genetic counseling and subsequent genetic testing. Care delivery models using pre-test and post-test counseling are not scalable, which contributes to barriers in accessing genetics services. These barriers are even more pronounced for patients in historically underserved populations. We have designed a multimodal intervention to improve subsequent cancer surveillance, by improving the identification of patients at risk for familial cancer syndromes, reducing barriers to genetic counseling/testing, and increasing patient understanding of complex genetic results. We are evaluating this intervention in two large, integrated healthcare systems that serve diverse patient populations (NCT03426878). The primary outcome is the number of diagnostic (hereditary cancer syndrome) findings. We are examining the clinical and personal utility of streamlined pathways to genetic testing using electronic medical record data, surveys, and qualitative interviews. We will assess downstream care utilization of individuals receiving usual clinical care vs. genetic testing through the study. We will evaluate the impacts of a literacy-focused genetic counseling approach versus usual care genetic counseling on care utilization and participant understanding, satisfaction, and family communication. By recruiting participants belonging to historically underserved populations, this study is uniquely positioned to evaluate the potential of a novel genetics care delivery program to reduce care disparities.

The My Cancer Genome clinical trial data model and trial curation workflow

OBJECTIVE

As clinical trials evolve in complexity, clinical trial data models that can capture relevant trial data in meaningful, structured annotations and computable forms are needed to support accrual.

MATERIAL AND METHODS

We have developed a clinical trial information model, curation information system, and a standard operating procedure for consistent and accurate annotation of cancer clinical trials. Clinical trial documents are pulled into the curation system from publicly available sources. Using a web-based interface, a curator creates structured assertions related to disease-biomarker eligibility criteria, therapeutic context, and treatment cohorts by leveraging our data model features. These structured assertions are published on the My Cancer Genome (MCG) website.

RESULTS

To date, over 5000 oncology trials have been manually curated. All trial assertion data are available for public view on the MCG website. Querying our structured knowledge base, we performed a landscape analysis to assess the top diseases, biomarker alterations, and drugs featured across all cancer trials.

DISCUSSION

Beyond curating commonly captured elements, such as disease and biomarker eligibility criteria, we have expanded our model to support the curation of trial interventions and therapeutic context (ie, neoadjuvant, metastatic, etc.), and the respective biomarker-disease treatment cohorts. To the best of our knowledge, this is the first effort to capture these fields in a structured format.

CONCLUSION

This paper makes a significant contribution to the field of biomedical informatics and knowledge dissemination for precision oncology via the MCG website.

KEY WORDS

knowledge representation, My Cancer Genome, precision oncology, knowledge curation, cancer informatics, clinical trial data model.

Adaptation and early implementation of the PREdiction model for gene mutations (PREMM5™) for lynch syndrome risk assessment in a diverse population

Lynch syndrome (LS) is the most common inherited cause of colorectal and endometrial cancers. Identifying individuals at risk for LS without personal cancer history requires detailed collection and assessment of family health history. However, barriers exist to family health history collection, especially in historically underserved populations. To improve LS risk assessment in historically underserved populations, we adapted the provider-facing PREdiction Model for gene Mutations (PREMM₅™ model), a validated LS risk assessment model, into a patient-facing electronic application through an iterative development process involving expert and patient stakeholders. We report on preliminary findings based on the first 500 individuals exposed to the adapted application in a primary care population enriched for low-literacy and low-resource patients. Major adaptations to the PREMM₅™ provider module included reduction in reading level, addition of interactive literacy aids, incorporation of family history assessment for both maternal and paternal sides of the family, and inclusion of questions about individual relatives or small groups of relatives to reduce cognitive burden. In the first 500 individuals, 90% completed the PREMM₅™ independently; of those, 94% did so in 5 min or less (ranged from 0.2 to 48.8 min). The patient-facing application was able to accurately classify 84% of patients as having clinically significant or not clinically significant LS risk. Our preliminary results suggest that in this diverse study population, most participants were able to rapidly, accurately, and independently complete an interactive application collecting family health history assessment that accurately assessed for Lynch syndrome risk.

Participant Reactions to a Literacy-Focused, Web-Based Informed Consent Approach for a Genomic Implementation Study

BACKGROUND

Clinical genomic implementation studies pose challenges for informed consent. Consent forms often include complex language and concepts, which can be a barrier to diverse enrollment, and these studies often blur traditional research-clinical boundaries. There is a move toward self-directed, web-based research enrollment, but more evidence is needed about how these enrollment approaches work in practice. In this study, we developed and evaluated a literacy-focused, web-based consent approach to support enrollment of diverse participants in an ongoing clinical genomic implementation study. Methods: As part of the Cancer Health Assessments Reaching Many (CHARM) study, we developed a web-based consent approach that featured plain language, multimedia, and separate descriptions of clinical care and research activities. CHARM offered clinical exome sequencing to individuals at high risk of hereditary cancer. We interviewed CHARM participants about their reactions to the consent approach. We audio recorded, transcribed, and coded interviews using a deductively and inductively derived codebook. We reviewed coded excerpts as a team to identify overarching themes. Results: We conducted 32 interviews, including 12 (38%) in Spanish. Most (69%) enrolled without assistance from study staff, usually on a mobile phone. Those who completed enrollment in one day spent an average of 12 minutes on the consent portion. Interviewees found the information simple to read but comprehensive, were neutral to positive about the multimedia support, and identified increased access to testing in the study as the key difference from clinical care. Conclusions: This study showed that interviewees found our literacy-focused, web-based consent approach acceptable; did not distinguish the consent materials from other online study processes; and valued getting access to testing in the study. Overall, conducting empirical bioethics research in an ongoing clinical trial was useful to demonstrate the acceptability of our novel consent approach but posed practical challenges.

Abstract PR02: Using web-based tools to assess familial cancer risk in diverse populations

Introduction: The Cancer Health Risk Assessments Reaching Many (CHARM) study (NCT03426878) aims to increase access to genetic testing for hereditary cancer in low-income, low-literacy, and minority populations (hereafter referred to as “underserved”). To implement the study, we have capitalized on the availability of electronic medical record (EMR) systems, developed innovative web-based tools, and designed a novel telemedicine protocol for return of clinical genetic testing results.

Methods: Patients aged 18-49 years are recruited from two centers: Kaiser Permanente Northwest (KPNW; an integrated health care system in Portland, OR) and Denver Health (DH; a federally qualified health care center in Denver, CO). Specific protocols were developed to identify potentially eligible patients from the EMR and invite them to complete a web-based family history assessment. KPNW patients were recruited using email, text messaging, and in-clinic booths; DH patients were recruited via mail, phone, and provider referral. Validated risk assessment tools for Lynch syndrome (PREMM5) and heredity breast and ovarian cancer syndrome (B-RST) were adapted for our low-literacy and bilingual (English and Spanish) target population. Genetic testing is offered to patients with greater than average risk for hereditary cancer, or where risk cannot be assessed because of unknown family history or limited family structure. Eligible patients review a multipart, multimedia online consent. Those who consent to participate provide a saliva sample for clinical exome sequencing. Genetic counselors return results by telephone using traditional (usual care active comparator) or modified, communication-focused (experimental) counseling for pathogenic variants, likely pathogenic variants, and select variants of uncertain significance in 39 genes related to cancer risk, pathogenic variants in 79 genes related to medically actionable secondary findings, and 14 genes related to carrier status.

Results: In the first four months of recruitment, 258 patients have completed the risk assessment tool (48% are underserved). Of those, 180 (70%) had greater than average risk of hereditary cancer (or limited family history information) and were invited to participate (53% were underserved); 86% of underserved patients and 78% of patients who do not meet criteria for the underserved category have consented. The vast majority of participants complete enrollment without assistance from study staff, and in-person visits are not required for participation. Telephone genetic test result disclosure will begin in December 2018.

Conclusions: We have successfully developed online tools for cancer risk assessment that are accessible to underserved and low-literacy populations. These tools may be a cost-effective approach for improving the capture of family history data in the EMR. It does not require a provider to gather the information and the patient gets immediate feedback on results of the risk assessment and appropriate next steps.

This abstract is also being presented as Poster A37.

Citation Format: Heather Spencer Feigelson, Kathleen F. Mittendorf, Tia L. Kauffman, Katherine Anderson, Sonia Okuyama, Benjamin Wilfond, Gail P. Jarvik, Laura M. Amendola, Carmit McMullen, Fances Lynch, Donna Eubanks, Elizabeth Shuster, Jake Allen, Stephanie A. Kraft, Galen Joseph, Sandra Soo-Jin Lee, Katrina A.B. Goddard. Using web-based tools to assess familial cancer risk in diverse populations [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr PR02.

Bicelles Rich in both Sphingolipids and Cholesterol and Their Use in Studies of Membrane Proteins

How the distinctive lipid composition of mammalian plasma membranes impacts membrane protein structure is largely unexplored, partly because of the dearth of isotropic model membrane systems that contain abundant sphingolipids and cholesterol. This gap is addressed by showing that sphingomyelin and cholesterol-rich (SCOR) lipid mixtures with phosphatidylcholine can be cosolubilized by n-dodecyl-β-melibioside to form bicelles. Small-angle X-ray and neutron scattering, as well as cryo-electron microscopy, demonstrate that these assemblies are stable over a wide range of conditions and exhibit the bilayered-disc morphology of ideal bicelles even at low lipid-to-detergent mole ratios. SCOR bicelles are shown to be compatible with a wide array of experimental techniques, as applied to the transmembrane human amyloid precursor C99 protein in this medium. These studies reveal an equilibrium between low-order oligomer structures that differ significantly from previous experimental structures of C99, providing an example of how ordered membranes alter membrane protein structure.

Recommended care and care adherence following a diagnosis of Lynch syndrome: a mixed-methods study

BACKGROUND

Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRC) syndrome. This study assesses trends in diagnosis of LS and adherence to recommended LS-related care in a large integrated healthcare organization (~ 575,000 members).

METHODS

Electronic medical record (EMR) data (1999-2015) were examined to identify patients with a diagnosis of LS. We examined their LS-associated care recommendations and adherence to these recommendations. Qualitative patient and provider interviews were conducted with the aim of identifying opportunities for improved care delivery.

RESULTS

We identified 74 patients with a diagnosis of LS; 64% were diagnosed with a LS-related malignancy prior to their diagnosis of LS. The time to LS diagnosis following development of a LS-related cancer decreased over time: before 2009 11% of individuals received a diagnosis of LS within 1 year of developing a LS-related cancer compared to 83% after 2009 (p < 0.0001). Colonoscopy recommendations were documented in the EMR for almost all patients with LS (96%). Documentation of other recommendations for cancer surveillance was less commonly found. Overall, patient adherence to colonoscopy was high (M = 81.5%; SD = 32.7%), and adherence to other recommendations varied. To improve care coordination, patients and providers suggested providing automated reminder prompts for LS-related surveillance, adding a LS-specific diagnosis code, and providing guidelines for LS-related surveillance in the EMR.

CONCLUSIONS

We identified fewer than expected patients with LS in our large care system, indicating that there is still a diagnostic care gap. However, patients with LS were likely to receive and follow CRC surveillance recommendations. Recommendations for and adherence to extracolonic surveillance were variable. Improved care coordination and clearer documentation of the LS diagnosis is needed.

Evidence-based assessments of clinical actionability in the context of secondary findings: Updates from ClinGen's Actionability Working Group

The use of genome-scale sequencing allows for identification of genetic findings beyond the original indication for testing (secondary findings). The ClinGen Actionability Working Group's (AWG) protocol for evidence synthesis and semi-quantitative metric scoring evaluates four domains of clinical actionability for potential secondary findings: severity and likelihood of the outcome, and effectiveness and nature of the intervention. As of February 2018, the AWG has scored 127 genes associated with 78 disorders (up-to-date topics/scores are available at www.clinicalgenome.org). Scores across these disorders were assessed to compare genes/disorders recommended for return as secondary findings by the American College of Medical Genetics and Genomics (ACMG) with those not currently recommended. Disorders recommended by the ACMG scored higher on outcome-related domains (severity and likelihood), but not on intervention-related domains (effectiveness and nature of the intervention). Current practices indicate that return of secondary findings will expand beyond those currently recommended by the ACMG. The ClinGen AWG evidence reports and summary scores are not intended as classifications of actionability, rather they provide a resource to aid decision makers as they determine best practices regarding secondary findings. The ClinGen AWG is working with the ACMG Secondary Findings Committee to update future iterations of their secondary findings list.

Expert and lay perspectives on burden, risk, tolerability, and acceptability of clinical interventions for genetic disorders

PURPOSE

The Clinical Genome Resource (ClinGen) Actionability Working Group (AWG) developed a semiquantitative scoring metric to rate clinical actionability of genetic disorders and associated genes in four domains: (1) severity of the outcome, (2) likelihood of the outcome, (3) effectiveness of the intervention to prevent/minimize the outcome, and (4) nature of the intervention with respect to burden, risk, tolerability, and acceptability to the patient. This study aimed to assess whether nature of the intervention scores assigned by AWG experts reflected lay perceptions of intervention burden, risk, tolerability, and acceptability given the subjectivity of this domain.

METHODS

In July 2017, a general population sample of 1344 adults completed the study. Each participant was asked to read 1 of 24 plain language medical intervention synopses and answer questions related to its burden, risk, tolerability, and acceptability. We conducted three multilevel mixed model analyses predicting the perceived burden, perceived risk, and perceived overall nature of the intervention.

RESULTS

As AWG nature of the intervention scores increased, lay perceptions of intervention burden and risk decreased, and perceptions of tolerability and acceptability increased.

CONCLUSION

The findings show alignment between the ClinGen actionability scoring metric and lay perceptions of the nature of the intervention.

Primary Ovarian Insufficiency and Adolescent Vaccination

BACKGROUND

Published case series have suggested a potential association between human papillomavirus (HPV) vaccination and primary ovarian insufficiency (POI). We describe POI incidence and estimate POI risk after HPV; tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, adsorbed (Tdap); inactivated influenza (II); and meningococcal conjugate (MenACWY) vaccination.

METHODS

We searched Kaiser Permanente Northwest electronic health records for outpatient diagnoses suggestive of POI in female patients aged 11 to 34 years between 2006 and 2014. We reviewed and adjudicated the medical record to confirm diagnoses and estimate symptom onset dates. We excluded cases with known causes and calculated the incidence of idiopathic POI. We estimated risk by calculating hazard ratios and 95% confidence intervals (CIs).

RESULTS

From a cohort of 199 078 female patients, we identified 120 with diagnoses suggestive of POI. After adjudication and exclusion of 26 POI cases with known causes, we confirmed 46 idiopathic POI cases. POI incidence was low in 11- to 14-year-olds (0.87 per 1 000 000 person-months) and increased with age. One confirmed case patient received the HPV vaccine 23 months before the first clinical evaluation for delayed menarche. The adjusted hazard ratio was 0.30 (95% CI: 0.07-1.36) after HPV, 0.88 (95% CI: 0.37-2.10) after Tdap, 1.42 (95% CI: 0.59-3.41) after II, and 0.94 (95% CI: 0.27-3.23) after MenACWY vaccination.

CONCLUSIONS

We did not find a statistically significant elevated risk of POI after HPV, Tdap, II, or MenACWY vaccination in this population-based retrospective cohort study. These findings should lessen concern about POI risk after adolescent vaccination.

Peripheral myelin protein 22 alters membrane architecture

Peripheral myelin protein 22 (PMP22) is highly expressed in myelinating Schwann cells of the peripheral nervous system. PMP22 genetic alterations cause the most common forms of Charcot-Marie-Tooth disease (CMTD), which is characterized by severe dysmyelination in the peripheral nerves. However, the functions of PMP22 in Schwann cell membranes remain unclear. We demonstrate that reconstitution of purified PMP22 into lipid vesicles results in the formation of compressed and cylindrically wrapped protein-lipid vesicles that share common organizational traits with compact myelin of peripheral nerves in vivo. The formation of these myelin-like assemblies depends on the lipid-to-PMP22 ratio, as well as on the PMP22 extracellular loops. Formation of the myelin-like assemblies is disrupted by a CMTD-causing mutation. This study provides both a biochemical assay for PMP22 function and evidence that PMP22 directly contributes to membrane organization in compact myelin.

Utility of adding clinical data to a molecular results portal for improving clinical trial prescreening efficiency

e18182

Background: Bioportals that aggregate patient genomic results and diagnosis data elements can be used as a tool for identifying potentially eligible patients for molecularly-driven clinical trials. However, over time, increasing numbers of patients will be deceased, making this process less efficient. Methods: We sought to evaluate the addition of minimal clinical data to a clinical trial prescreening workflow utilizing these bioportals. We selected three molecularly-driven clinical trials currently enrolling patients at Vanderbilt-Ingram Cancer Center and evaluated the incremental contribution of genomic and clinical data to refinement of cohort identification. Utilizing data from the enterprise data warehouse (EDW), we assessed the potentially eligible patient population after addition of gene-level, alteration-level, vital status (known to be deceased), and date of last contact data elements to the data extraction query. Results: Utilizing gene-level and diagnosis data elements only, 68 potentially eligible patients were identified for these trials from a total of 7,200 patients whose NGS data was added to the EDW between 2010 and 2016. Addition of alteration-level detail eliminated 29% of these patients. Of the 53 remaining patients, incorporating vital status resulted in paring the potentially eligible cohorts by an additional 42%. Conclusions: This study demonstrates the added value of querying structured clinical and molecular data stored in the EDW to improve prescreen workflow efficiency and decrease manual review requirements. [Table: see text]

Assessment of actionability of cancer genomic testing panels based on a structured clinical trial knowledge base

6533

Background: Today’s oncologist is responsible for choosing appropriate cancer genomics tests to inform patient treatment from multiple available platforms, weighing cost, availability, sensitivity and specificity, and clinical actionability. Knowledge-driven clinical decision support tools can assist clinicians in choosing the panel that is most informative in a given clinical space. Methods: Using a queryable knowledgebase of >1800 active clinical trials containing structured eligibility criteria curations for diagnosis and genomic alterations, we compared two CLIA-regulated genomic panels for clinical actionability over the landscape of solid, breast, and lung cancer clinical trials. Results: The larger panel (73 genes) was more actionable than the smaller panel (62 genes) in the breast cancer (10x more trials returned) and solid tumor (2.7x more trials returned) clinical trial space, while the smaller panel returned 1.2x more trials in the lung cancer space (see table). Conclusions: This analysis demonstrates that patient diagnosis has a significant effect on the potential clinical actionability of a given genomic panel. Further, this analysis demonstrates the clinical utility of knowledge-driven clinical decision support tools for test selection, especially given the often-limited tumor sample available, cost of genomic panel testing, and continuously shifting trial landscape. [Table: see text]

While the revolution will not be crystallized, biochemistry reigns supreme

Single-particle cryo-electron microscopy (EM) is currently gaining attention for the ability to calculate structures that reach sub-5 Å resolutions; however, the technique is more than just an alternative approach to X-ray crystallography. Molecular machines work via dynamic conformational changes, making structural flexibility the hallmark of function. While the dynamic regions in molecules are essential, they are also the most challenging to structurally characterize. Single-particle EM has the distinct advantage of being able to directly visualize purified molecules without the formation of ordered arrays of molecules locked into identical conformations. Additionally, structures determined using single-particle EM can span resolution ranges from very low- to atomic-levels (>30-1.8 Å), sometimes even in the same structure. The ability to accommodate various resolutions gives single-particle EM the unique capacity to structurally characterize dynamic regions of biological molecules, thereby contributing essential structural information needed for the development of molecular models that explain function. Further, many important molecular machines are intrinsically dynamic and compositionally heterogeneous. Structures of these complexes may never reach sub-5 Å resolutions due to this flexibility required for function. Thus, the biochemical quality of the sample, as well as, the calculation and interpretation of low- to mid-resolution cryo-EM structures (30-8 Å) remains critical for generating insights into the architecture of many challenging biological samples that cannot be visualized using alternative techniques.

Conformational Stability and Pathogenic Misfolding of the Integral Membrane Protein PMP22

Despite broad biochemical relevance, our understanding of the physiochemical reactions that limit the assembly and cellular trafficking of integral membrane proteins remains superficial. In this work, we report the first experimental assessment of the relationship between the conformational stability of a eukaryotic membrane protein and the degree to which it is retained by cellular quality control in the secretory pathway. We quantitatively assessed both the conformational equilibrium and cellular trafficking of 12 variants of the α-helical membrane protein peripheral myelin protein 22 (PMP22), the intracellular misfolding of which is known to cause peripheral neuropathies associated with Charcot–Marie–Tooth disease (CMT). We show that the extent to which these mutations influence the energetics of Zn(II)-mediated PMP22 folding is proportional to the observed reduction in cellular trafficking efficiency. Strikingly, quantitative analyses also reveal that the reduction of motor nerve conduction velocities in affected patients is proportional to the extent of the mutagenic destabilization. This finding provides compelling evidence that the effects of these mutations on the energetics of PMP22 folding lie at the heart of the molecular basis of CMT. These findings highlight conformational stability as a key factor governing membrane protein biogenesis and suggest novel therapeutic strategies for CMT.

The homology model of PMP22 suggests mutations resulting in peripheral neuropathy disrupt transmembrane helix packing

Peripheral myelin protein 22 (PMP22) is a tetraspan membrane protein strongly expressed in myelinating Schwann cells of the peripheral nervous system. Myriad missense mutations in PMP22 result in varying degrees of peripheral neuropathy. We used Rosetta 3.5 to generate a homology model of PMP22 based on the recently published crystal structure of claudin-15. The model suggests that several mutations known to result in neuropathy act by disrupting transmembrane helix packing interactions. Our model also supports suggestions from previous studies that the first transmembrane helix is not tightly associated with the rest of the helical bundle.

Impact of bilayer lipid composition on the structure and topology of the transmembrane amyloid precursor C99 protein

C99 (also known as β-CTF) is the 99 residue transmembrane C-terminal domain (residues 672–770) of the amyloid precursor protein and is the immediate precursor of the amyloid-β (Aβ) polypeptides. To test the dependence of the C99 structure on the composition of the host model membranes, NMR studies of C99 were conducted both in anionic lyso-myristoylphosphatidylglycerol (LMPG) micelles and in a series of five zwitterionic bicelle compositions involving phosphatidylcholine and sphingomyelin in which the acyl chain lengths of these lipid components varied from 14 to 24 carbons. Some of these mixtures are reported for the first time in this work and should be of broad utility in membrane protein research. The site-specific backbone ¹⁵N and ¹H chemical shifts for C99 in LMPG and in all five bicelle mixtures were seen to be remarkably similar, indicating little dependence of the backbone structure of C99 on the composition of the host model membrane. However, the length of the transmembrane span was seen to vary in a manner that alters the positioning of the γ-secretase cleavage sites with respect to the center of the bilayer. This observation may contribute to the known dependency of the Aβ42-to-Aβ40 production ratio on both membrane thickness and the length of the C99 transmembrane domain.

Reversible folding of human peripheral myelin protein 22, a tetraspan membrane protein

Misfolding of the α-helical membrane protein peripheral myelin protein 22 (PMP22) has been implicated in the pathogenesis of the common neurodegenerative disease known as Charcot-Marie-Tooth disease (CMTD) and also several other related peripheral neuropathies. Emerging evidence suggests that the propensity of PMP22 to misfold in the cell may be due to an intrinsic lack of conformational stability. Therefore, quantitative studies of the conformational equilibrium of PMP22 are needed to gain insight into the molecular basis of CMTD. In this work, we have investigated the folding and unfolding of wild type (WT) human PMP22 in mixed micelles. Both kinetic and thermodynamic measurements demonstrate that the denaturation of PMP22 by n-lauroyl sarcosine (LS) in dodecylphosphocholine (DPC) micelles is reversible. Assessment of the conformational equilibrium indicates that a significant fraction of unfolded PMP22 persists even in the absence of the denaturing detergent. However, we find the stability of PMP22 is increased by glycerol, which facilitates quantitation of thermodynamic parameters. To our knowledge, this work represents the first report of reversible unfolding of a eukaryotic multispan membrane protein. The results indicate that WT PMP22 possesses minimal conformational stability in micelles, which parallels its poor folding efficiency in the endoplasmic reticulum. Folding equilibrium measurements for PMP22 in micelles may provide an approach to assess the effects of cellular metabolites or potential therapeutic agents on its stability. Furthermore, these results pave the way for future investigation of the effects of pathogenic mutations on the conformational equilibrium of PMP22.

Tailoring of membrane proteins by alternative splicing of pre-mRNA

Alternative splicing (AS) of RNA is a key mechanism for diversification of the eukaryotic proteome. In this process, different mRNA transcripts can be produced through altered excision and/or inclusion of exons during processing of the pre-mRNA molecule. Since its discovery, AS has been shown to play roles in protein structure, function, and localization. Dysregulation of this process can result in disease phenotypes. Moreover, AS pathways are promising therapeutic targets for a number of diseases. Integral membrane proteins (MPs) represent a class of proteins that may be particularly amenable to regulation by alternative splicing because of the distinctive topological restraints associated with their folding, structure, trafficking, and function. Here, we review the impact of AS on MP form and function and the roles of AS in MP-related disorders such as Alzheimer's disease.

Tolerance to changes in membrane lipid composition as a selected trait of membrane proteins

Membrane lipid composition can vary dramatically across the three domains of life and even within single organisms. Here we review evidence that the lipid-exposed surfaces of membrane proteins have generally evolved to maintain correct structure and function in the face of major changes in lipid composition. Such tolerance has allowed evolution to extensively remodel membrane lipid compositions during the emergence of new species without having to extensively remodel the associated membrane proteins. The tolerance of membrane proteins also permits single-cell organisms to vary their membrane lipid composition in response to their changing environments and allows dynamic and organelle-specific variations in the lipid compositions of eukaryotic cells. Membrane protein structural biology has greatly benefited from this seemingly intrinsic property of membrane proteins: the majority of structures determined to date have been characterized under model membrane conditions that little resemble those of native membranes. Nevertheless, with a few notable exceptions, most experimentally determined membrane protein structures appear, to a good approximation, to faithfully report on native structure.